Four problems related to coolant leaking have been reported for the 2004 Porsche 911 Gt3. The most recently reported issues are listed below.
A coolant line fitting that is epoxied into the block became suddenly and completely disconnected. The coolant all flowed out of the leak nearly instantly. The pool of coolant created a hazard for following cars and the motor needed to be shut down immediately and the car towed to a service facility.
Coolant pipes leaking after drive.
Early coolant pipe leakage at one of the fittings. Unable to repair without engine removal. I chose to repair all coolant fittings at that time.
Coolant lines came loose where they were glued to the motor. I have seen catastrophic failures, and did not want to have an accident. Had the motor removed, and repair shop said some of mine were loose and showed signs of leaking. Had all welded at an independent shop. Porsche would not fix unless there was a failure, and would only re-glue those that were loose.